Editorial Type:
Article
Article Type:
Research Article

External Influences on Nocturnal Thermally Driven Flows in a Deep Valley

Juerg Schmidli National Center for Atmospheric Research,* Boulder, Colorado

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Gregory S. Poulos National Center for Atmospheric Research,* Boulder, Colorado

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Megan H. Daniels Department of Civil and Environmental Engineering, University of California, Berkeley, Berkeley, California

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Fotini K. Chow Department of Civil and Environmental Engineering, University of California, Berkeley, Berkeley, California

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Print Publication:
01 Jan 2009
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Terrain-Induced Rotor Experiment (T-Rex)
DOI:
https://doi.org/10.1175/2008JAMC1852.1
Page(s):
3–23
Restricted access

Abstract

The dynamics that govern the evolution of nighttime flows in a deep valley, California’s Owens Valley, are analyzed. Measurements from the Terrain-Induced Rotor Experiment (T-REX) reveal a pronounced valley-wind system with often nonclassical flow evolution. Two cases with a weak high pressure ridge over the study area but very different valley flow evolution are presented. The first event is characterized by the appearance of a layer of southerly flow after midnight local time, sandwiched between a thermally driven low-level downvalley (northerly) flow and a synoptic northwesterly flow aloft. The second event is characterized by an unusually strong and deep downvalley jet, exceeding 15 m s−1. The analysis is based on the T-REX measurement data and the output of high-resolution large-eddy simulations using the Advanced Regional Prediction System (ARPS). Using horizontal grid spacings of 1 km and 350 m, ARPS reproduces the observed flow features for these two cases very well. It is found that the low-level along-valley forcing of the valley wind is the result of a superposition of the local thermal forcing and a midlevel (2–2.5 km MSL) along-valley pressure forcing. The analysis shows that the large difference in valley flow evolution derives primarily from differences in the midlevel pressure forcing, and that the Owens Valley is particularly susceptible to these midlevel external influences because of its specific geometry. The results demonstrate the delicate interplay of forces that can combine to determine the valley flow structure on any given night.

* The National Center for Atmospheric Research is sponsored by the National Science Foundation.

Corresponding author address: Juerg Schmidli, Universitätstrasse 16, 8092 Zürich, Switzerland. Email: jschmidli@env.ethz.ch.

This article included in the Terrain-Induced Rotor Experiment (T-Rex) special collection.

Abstract

The dynamics that govern the evolution of nighttime flows in a deep valley, California’s Owens Valley, are analyzed. Measurements from the Terrain-Induced Rotor Experiment (T-REX) reveal a pronounced valley-wind system with often nonclassical flow evolution. Two cases with a weak high pressure ridge over the study area but very different valley flow evolution are presented. The first event is characterized by the appearance of a layer of southerly flow after midnight local time, sandwiched between a thermally driven low-level downvalley (northerly) flow and a synoptic northwesterly flow aloft. The second event is characterized by an unusually strong and deep downvalley jet, exceeding 15 m s−1. The analysis is based on the T-REX measurement data and the output of high-resolution large-eddy simulations using the Advanced Regional Prediction System (ARPS). Using horizontal grid spacings of 1 km and 350 m, ARPS reproduces the observed flow features for these two cases very well. It is found that the low-level along-valley forcing of the valley wind is the result of a superposition of the local thermal forcing and a midlevel (2–2.5 km MSL) along-valley pressure forcing. The analysis shows that the large difference in valley flow evolution derives primarily from differences in the midlevel pressure forcing, and that the Owens Valley is particularly susceptible to these midlevel external influences because of its specific geometry. The results demonstrate the delicate interplay of forces that can combine to determine the valley flow structure on any given night.

* The National Center for Atmospheric Research is sponsored by the National Science Foundation.

Corresponding author address: Juerg Schmidli, Universitätstrasse 16, 8092 Zürich, Switzerland. Email: jschmidli@env.ethz.ch.

This article included in the Terrain-Induced Rotor Experiment (T-Rex) special collection.

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  • Banta, R. M., 1986: Daytime boundary-layer evolution over mountainous terrain. Part II: Numerical studies of upslope flow duration. Mon. Wea. Rev., 114 , 1112–1130.

    • Search Google Scholar
    • Export Citation

  • Banta, R. M., and W. R. Cotton, 1981: An analysis of the structure of local wind systems in a broad mountain bassin. J. Appl. Meteor., 20 , 1255–1266.

    • Search Google Scholar
    • Export Citation

  • Banta, R. M., and P. T. Gannon, 1995: Influence of soil moisture on simulations of katabatic flow. Theor. Appl. Climatol., 52 , 85–94.

  • Barr, S., and M. M. Orgill, 1989: Influence of external meteorology on nocturnal valley drainage winds. J. Appl. Meteor., 28 , 497–517.

    • Search Google Scholar
    • Export Citation

  • Byun, D. W., 1990: On the analytical solutions of flux-profile relationships for the atmospheric surface layer. J. Appl. Meteor., 29 , 652–657.

    • Search Google Scholar
    • Export Citation

  • Chou, M-D., 1990: Parameterization for the absorption of solar radiation by O2 and CO2 with application for climate studies. J. Climate, 3 , 209–217.

    • Search Google Scholar
    • Export Citation

  • Chou, M-D., 1992: A solar radiation model for climate studies. J. Atmos. Sci., 49 , 762–772.

  • Chou, M-D., and M. J. Suarez, 1994: An efficient thermal infrared radiation parameterization for use in general circulation models. NASA Tech. Memo. 104606, Vol. 3, 102 pp.

    • Search Google Scholar
    • Export Citation

  • Chow, F. K., A. P. Weigel, R. L. Street, M. W. Rotach, and M. Xue, 2006: High-resolution large-eddy simulations of flow in a steep Alpine valley. Part I: Methodology, verification, and sensitivity experiments. J. Appl. Meteor. Climatol., 45 , 63–86.

    • Search Google Scholar
    • Export Citation

  • Cohn, S. A., W. O. J. Brown, and V. Grubisic, 2005: The Mobile Integrated Sounding System (MISS): Description and lessons from the Sierra Rotors Project. Preprints, 13th Symp. on Meteorological Observations and Instrumentation, Savannah, GA, Amer. Meteor. Soc., 7.2. [Available online at http://ams.confex.com/ams/pdfpapers/94055.pdf.].

    • Search Google Scholar
    • Export Citation

  • Colette, A., F. K. Chow, and R. L. Steet, 2003: A numerical study of inversion-layer breakup and the effects of topographic shading in idealized valleys. J. Appl. Meteor., 42 , 1255–1272.

    • Search Google Scholar
    • Export Citation

  • Coulter, R. L., and P. Gudiksen, 1995: The dependence of canyon winds on surface cooling and external forcing in Colorado’s Front Range. J. Appl. Meteor., 34 , 1419–1429.

    • Search Google Scholar
    • Export Citation

  • Daniels, M. H., F. K. Chow, and G. S. Poulos, 2006: Effects of soil moisture initialization on simulations of atmospheric boundary layer evolution in Owens Valley. Extended Abstracts, 12th Conf. on Mountain Meteorology, Santa Fe, NM, Amer. Meteor. Soc., 7.2. [Available online at http://ams.confex.com/ams/pdfpapers/114757.pdf.].

    • Search Google Scholar
    • Export Citation

  • Davies-Jones, R., 2003: An expression for effective buoyancy in surroundings with horizontal density gradients. J. Atmos. Sci., 60 , 2922–2925.

    • Search Google Scholar
    • Export Citation

  • Deardorff, J. W., 1972: Parametrization of the planetary boundary layer for use in general circulation models. Mon. Wea. Rev., 100 , 93–106.

    • Search Google Scholar
    • Export Citation

  • Deardorff, J. W., 1980: Stratocumulus-capped mixed layers derived from a 3-dimensional model. Bound.-Layer Meteor., 18 , 495–527.

  • De Wekker, S. F. J., S. Zhong, J. D. Fast, and C. D. Whiteman, 1998: A numerical study of the thermally driven plain-to-basin wind over idealized basin topographies. J. Appl. Meteor., 37 , 606–622.

    • Search Google Scholar
    • Export Citation

  • De Wekker, S. F. J., D. G. Steyn, J. D. Fast, M. W. Rotach, and S. Zhong, 2005: The performance of RAMS in representing the convective boundary layer structure in a very steep valley. Environ. Fluid Mech., 5 , 35–62.

    • Search Google Scholar
    • Export Citation

  • Doran, J. C., 1991: The effects of ambient winds on valley drainage flows. Bound-Layer Meteor., 55 , 177–189.

  • Doran, J. C., J. D. Fast, and J. Horel, 2002: The VTMX 2000 campaign. Bound.-Layer Meteor., 83 , 537–551.

  • Egger, J., S. Bajrachaya, U. Egger, R. Heinrich, J. Reuder, P. Shayka, H. Wendth, and V. Wirth, 2000: Diurnal winds in the Himalayan Kali Gandaki Valley. Part I: Observations. Mon. Wea. Rev., 128 , 1106–1122.

    • Search Google Scholar
    • Export Citation

  • Estournel, C., and D. Guedalia, 1985: Influence of geostrophic wind on atmospheric nocturnal cooling. J. Atmos. Sci., 42 , 2695–2698.

  • Fast, J. D., K. J. Allwine, R. N. Dietz, K. L. Clawson, and J. C. Torcolini, 2006: Dispersion of perfluorocarbon tracers within the Salt Lake valley during VTMX 2000. J. Appl. Meteor., 45 , 793–812.

    • Search Google Scholar
    • Export Citation

  • Fiedler, F., 1983: Einige Charakteristika der Strömung im Oberrheingraben. Wissenschaftliche Berichte des Instituts f¨r Meterologie und Klimaforschung der Universität Karlsruhe, Band 4, 113–123.

    • Search Google Scholar
    • Export Citation

  • Gross, G., and F. Wippermann, 1987: Channeling and countercurrent in the upper Rhine Valley: Numerical simulations. J. Climate Appl. Meteor., 26 , 1293–1304.

    • Search Google Scholar
    • Export Citation

  • Grubišic, V., and Coauthors, 2008: The terrain-induced rotor experiment: A field campaign overview including observational highlights. Bull. Amer. Meteor. Soc., 89 , 1513–1533.

    • Search Google Scholar
    • Export Citation

  • Gudiksen, P. H., J. M. Leone, C. W. King, D. Ruffieux, and W. D. Neff, 1992: Measurements and modeling of the effects of ambient meteorology on nocturnal drainage flows. J. Appl. Meteor., 31 , 1023–1032.

    • Search Google Scholar
    • Export Citation

  • Kossmann, M., and A. P. Sturman, 2003: Pressure-driven channeling effects in bent valleys. J. Appl. Meteor., 42 , 151–158.

  • Kuwagata, T., and F. Kimura, 1995: Daytime boundary layer evolution in a deep valley. Part I: Observations in the Ina Valley. J. Appl. Meteor., 34 , 1082–1091.

    • Search Google Scholar
    • Export Citation

  • Kuwagata, T., and F. Kimura, 1997: Daytime boundary layer evolution in a deep valley. Part II: Numerical simulation of the cross-valley circulation. J. Appl. Meteor., 36 , 883–895.

    • Search Google Scholar
    • Export Citation

  • Mahrt, L., 1982: Momentum balance of gravity flows. J. Atmos. Sci., 39 , 2701–2711.

  • McKee, T. B., and R. D. O’Neil, 1989: The role of valley geometry and energy budget in the formation of nocturnal valley winds. J. Appl. Meteor., 28 , 445–456.

    • Search Google Scholar
    • Export Citation

  • Merritt, D. A., 1995: A statistical averaging method for wind profiler Doppler spectra. J. Atmos. Oceanic Technol., 12 , 985–995.

  • Moeng, C-H., 1984: A large-eddy simulation model for the study of planetary boundary-layer turbulence. J. Atmos. Sci., 41 , 2052–2062.

  • Monin, A. S., and A. M. Obukhov, 1954: Basic laws of turbulent mixing in the ground layer of the atmosphere. Akad. Nauk SSSR Geofiz. Inst. Tr., 151 , 163–187.

    • Search Google Scholar
    • Export Citation

  • Morse, C. S., R. K. Goodrick, and L. B. Cornman, 2002: The NIMA method for improved moment estimation from Doppler spectra. J. Atmos. Oceanic Technol., 19 , 274–295.

    • Search Google Scholar
    • Export Citation

  • Noilhan, J., and S. Planton, 1989: A simple parameterization of land surface processes for meteorological models. Mon. Wea. Rev., 117 , 536–549.

    • Search Google Scholar
    • Export Citation

  • Noppel, H., and F. Fiedler, 2002: Mesoscale heat transport over complex terrain by slope winds—A conceptual model and numerical simulations. Bound.-Layer Meteor., 104 , 73–97.

    • Search Google Scholar
    • Export Citation

  • Oncley, S. P., and Coauthors, 2007: The Energy Balance Experiment EBEX-2000. Part I: Overview and energy balance. Bound.-Layer Meteor., 123 , 1–28.

    • Search Google Scholar
    • Export Citation

  • Ookouchi, Y., M. Segal, R. C. Kessler, and R. A. Pielke, 1984: Evaluation of soil moisture effects on the generation and modification of mesoscale circulations. Mon. Wea. Rev., 112 , 2281–2292.

    • Search Google Scholar
    • Export Citation

  • Parsons, D., and Coauthors, 1994: The integrated sounding system: Description and preliminary observations from TOGA COARE. Bull. Amer. Meteor. Soc., 75 , 553–567.

    • Search Google Scholar
    • Export Citation

  • Poulos, G. S., and S. P. Burns, 2003: An evaluation of bulk Ri-based surface layer flux formulas for stable and very stable conditions with intermittent turbulence. J. Atmos. Sci., 60 , 2523–2537.

    • Search Google Scholar
    • Export Citation

  • Poulos, G. S., J. E. Bossert, R. A. Pielke, and T. B. McKee, 2000: The interaction of katabatic flow and mountain waves. Part I: Observations and idealized simulations. J. Atmos. Sci., 57 , 1919–1936.

    • Search Google Scholar
    • Export Citation

  • Poulos, G. S., J. E. Bossert, T. B. McKee, and R. A. Pielke, 2007: The interaction of katabatic flow and mountain waves. Part II: Case study analysis and conceptual model. J. Atmos. Sci., 64 , 1857–1879.

    • Search Google Scholar
    • Export Citation

  • Rampanelli, G., D. Zardi, and R. Rotunno, 2004: Mechanisms of upvalley winds. J. Atmos. Sci., 61 , 3097–3111.

  • Ren, D., and M. Xue, 2004: A revised force-restore model for land surface modeling. J. Appl. Meteor., 43 , 1768–1782.

  • Rotach, M. W., and D. Zardi, 2007: On the boundary-layer structure over highly complex terrain: Key findings from MAP. Quart. J. Roy. Meteor. Soc., 133 , 937–948.

    • Search Google Scholar
    • Export Citation

  • Schmidli, J., and G. S. Poulos, 2006: High-resolution modeling of the nighttime boundary layer evolution in the Owens valley: Comparison to observations. Extended Abstracts, 12th Conf. on Mountain Meteorology, Santa Fe, NM, Amer. Meteor. Soc., 7.1. [Available online at http://ams.confex.com/ams/pdfpapers/114527.pdf.].

    • Search Google Scholar
    • Export Citation

  • Smith, C. M., and E. D. Skyllingstad, 2005: Numerical simulation of katabatic flow with changing slope angle. Mon. Wea. Rev., 133 , 3065–3080.

    • Search Google Scholar
    • Export Citation

  • Steeneveld, G. J., B. J. H. van de Wiel, and A. A. M. Holtslag, 2006: Modeling the evolution of the atmospheric boundary layer coupled to the land surface for three contrasting nights in CASES-99. J. Atmos. Sci., 63 , 920–935.

    • Search Google Scholar
    • Export Citation

  • Steinacker, R., 1984: Area-height distribution of a valley and its relation to the valley wind. Contrib. Atmos. Phys., 57 , 64–71.

  • Tao, W-K., S. Lang, J. Simpson, C-H. Sui, B. Ferrier, and M-D. Chou, 1996: Mechanism of cloud–radiation interaction in the tropics and midlatitude. J. Atmos. Sci., 53 , 2624–2651.

    • Search Google Scholar
    • Export Citation

  • Vergeiner, I., and E. Dreiseitl, 1987: Valley winds and slope winds—Observations and elementary thoughts. Meteor. Atmos. Phys., 36 , 264–286.

    • Search Google Scholar
    • Export Citation

  • Wagner, A., 1938: Theorie und Beobachtung der periodischen Gebirgswinde. Gerl. Beitr. Geophys., 52 , 408–449.

  • Weigel, A. P., F. K. Chow, M. W. Rotach, R. L. Street, and M. Xue, 2006: High-resolution large-eddy simulations of flow in a steep Alpine valley. Part II: Flow structure and heat budgets. J. Appl. Meteor. Climatol., 45 , 87–107.

    • Search Google Scholar
    • Export Citation

  • Weigel, A. P., F. K. Chow, and M. W. Rotach, 2007: The effect of mountainous topography on moisture exchange between the surface and the free atmosphere. Bound.-Layer Meteor., 125 , 227–244.

    • Search Google Scholar
    • Export Citation

  • Whiteman, C. D., 1989: Morning transition tracer experiments in a deep narrow valley. J. Appl. Meteor., 28 , 626–635.

  • Whiteman, C. D., 1990: Observations of thermally developed wind systems in mountainous terrain. Atmospheric Processes over Complex Terrain, Meteor. Monogr., No. 23, Amer. Meteor. Soc., 5–42.

    • Search Google Scholar
    • Export Citation

  • Whiteman, C. D., 2000: Mountain Meteorology: Fundamentals and Applications. Oxford University Press, 355 pp.

  • Whiteman, C. D., and J. C. Doran, 1993: The relationship between overlying synoptic-scale flows and winds within a valley. J. Appl. Meteor., 32 , 1669–1682.

    • Search Google Scholar
    • Export Citation

  • Wilczak, J. M., and Coauthors, 1995: Contamination of wind profiler data by migrating brids: Characteristics of corrupted data and potential solutions. J. Atmos. Oceanic Technol., 12 , 449–467.

    • Search Google Scholar
    • Export Citation

  • Xue, M., K. K. Droegemeier, and V. Wong, 2000: The Advanced Regional Prediction System (ARPS)—A multi-scale nonhydrostatic atmospheric simulation and prediction model. Part I: Model dynamics and verification. Meteor. Atmos. Phys., 75 , 161–193.

    • Search Google Scholar
    • Export Citation

  • Xue, M., and Coauthors, 2001: The Advanced Regional Prediction System (ARPS)—A multi-scale nonhydrostatic atmospheric simulation and prediction model. Part II: Model physics and applications. Meteor. Atmos. Phys., 76 , 143–165.

    • Search Google Scholar
    • Export Citation

  • Xue, M., D. H. Wang, J. D. Gao, K. Brewster, and K. K. Droegemeier, 2003: The Advanced Regional Prediction System (ARPS), storm-scale numerical weather prediction and data assimilation. Meteor. Atmos. Phys., 82 , 139–170.

    • Search Google Scholar
    • Export Citation

  • Zängl, G., J. Egger, and V. Wirth, 2001: Diurnal winds in the Himalayan Kali Gandaki Valley. Part II: Modeling. Mon. Wea. Rev., 129 , 1062–1080.

    • Search Google Scholar
    • Export Citation

  • Zhong, S. Y., and J. Fast, 2003: An evaluation of the MM5, RAMS, and Meso-Eta models at subkilometer resolution using VTMX field campaign data in the Salt Lake Valley. Mon. Wea. Rev., 131 , 1301–1322.

    • Search Google Scholar
    • Export Citation
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